Redesign the PDF report: landscape pages, headers/footers, icon, daily stats

Every report section now gets its own landscape A4 page (or, for
Dagoverzicht, one page per day) via a GlucoseReportPDF(FPDF) subclass
with a real header (section title, report version, insulin/pump/sensor
type from new REPORT_* env vars) and footer (page number, generation
timestamp, Nightscout link) on every page, plus an original SVG icon
in the header — inspired by the LibreView AGP report.

New "Insulineprofiel" PDF section mirrors the dashboard page (basal
bar chart, ISF/carb-ratio segments, DIA). Each Dagoverzicht day now
draws the same basal/bolus/carb/target overlays as the interactive
charts (matplotlib port of the Plotly helpers from #30) plus a new
per-day stats block (reporting.daily_stats: avg/min/max glucose,
total/basal/bolus/SMB insulin, hypo/hyper counts and durations).

Builds on #29 (profile data) and #30 (overlay logic/colors).

README.md

@@ -16,7 +16,8 @@ klinische rapportagepagina's (zie `docs/requirements-reporting.md` en
    diabetesteam, dus elke pagina zit achter een wachtwoord). `app.py` laadt
    `.env` zelf in (via `python-dotenv`), dus dit werkt hetzelfde onder
    PowerShell, cmd of bash — je hoeft de variabelen niet zelf in je shell te
-   zetten.
+   zetten. `REPORT_INSULIN_TYPE`/`REPORT_PUMP_TYPE`/`REPORT_SENSOR_TYPE` zijn
+   optioneel en puur informatief (getoond in de kop van het PDF-rapport).
 3. Lokaal draaien:
 
    ```powershell